Determining the SARS-CoV-2 serological immunoassay test performance indices based on the test results frequency distribution

Coronavirus disease 2019 (COVID-19) is known to induce robust antibody response in most of the affected individuals. The objective of the study was to determine if we can harvest the test sensitivity and specificity of a commercial serologic immunoassay merely based on the frequency distribution of the SARS-CoV-2 immunoglobulin (Ig) G concentrations measured in a population-based seroprevalence study. The current study was conducted on a subset of a previously published dataset from the canton of Geneva. Data were taken from two non-consecutive weeks (774 samples from May 4-9, and 658 from June 1-6, 2020). Assuming that the frequency distribution of the measured SARS-CoV-2 IgG is binormal (an educated guess), using a non-linear regression, we decomposed the distribution into its two Gaussian components. Based on the obtained regression coefficients, we calculated the prevalence of SARS-CoV-2 infection, the sensitivity and specificity, and the most appropriate cut-off value for the test. The obtained results were compared with those obtained from a validity study and a seroprevalence population-based study. The model could predict more than 90% of the variance observed in the SARS-CoV-2 IgG distribution. The results derived from our model were in good agreement with the results obtained from the seroprevalence and validity studies. Altogether 138 of 1432 people had SARS-CoV-2 IgG ≥ 0.90, the cut-off value which maximized the Youden’s index. This translates into a true prevalence of 7.0% (95% confidence interval 5.4% to 8.6%), which is in keeping with the estimated prevalence of 7.7% derived from our model. Our model can provide the true prevalence. Having an educated guess about the distribution of test results, the test performance indices can be derived with acceptable accuracy merely based on the test results frequency distribution without the need for conducting a validity study and comparing the test results against a gold-standard test

A Reliability-Generalization Study of Journal Peer Reviews: A Multilevel Meta-Analysis of Inter-Rater Reliability and Its Determinants

Background: This paper presents the first meta-analysis for the inter-rater reliability (IRR) of journal peer reviews. IRR is defined as the extent to which two or more independent reviews of the same scientific document agree. Methodology/Principal Findings: Altogether, 70 reliability coefficients (Cohen’s Kappa, intra-class correlation [ICC], and Pearson product-moment correlation [r]) from 48 studies were taken into account in the meta-analysis. The studies were based on a total of 19,443 manuscripts; on average, each study had a sample size of 311 manuscripts (minimum: 28, maximum: 1983). The results of the meta-analysis confirmed the findings of the narrative literature reviews published to date: The level of IRR (mean ICC/r 2 =.34, mean Cohen’s Kappa =.17) was low. To explain the study-to-study variation of the IRR coefficients, meta-regression analyses were calculated using seven covariates. Two covariates that emerged in the metaregression analyses as statistically significant to gain an approximate homogeneity of the intra-class correlations indicated that, firstly, the more manuscripts that a study is based on, the smaller the reported IRR coefficients are. Secondly, if the information of the rating system for reviewers was reported in a study, then this was associated with a smaller IRR coefficient than if the information was not conveyed. Conclusions/Significance: Studies that report a high level of IRR are to be considered less credible than those with a low level o

Case Reports- Isolated lingual leishmaniasis

Cutaneous leishmaniasis is endemic in Fars Province, southern Iran. However, mucosal leishmaniasis is extremely uncommon. Herein, we report a patient with isolated lingual leishmaniasis in an immunocompetent 40-year-old man. The lesion was totally excised. The patient was cured completely and is doing well after four years of follow-up, with no medical treatmen

Reproductive behaviour of mothers of children with beta-thalassaemia major ‫الكربى‬ ‫بالثالسيمية-بيتا‬ ‫املصابني‬ ‫األطفال‬ ‫ألمهات‬ ‫اإلنجايب‬ ‫السلوك‬

ABSTRACT Thalassaemia is the most common monogenic autosomal hereditary disease worldwide. This questionnaire-based cross-sectional study looked at the reproductive behaviour of 156 mothers of children affected with beta-thalassaemia major (Cooley anaemia) in Fars province, southern Islamic Republic of Iran. Regardless of the number of affected children, the parents of children with Cooley anaemia had an average of 3 unaffected children, the same as the average for the provincial population. The findings indicate that reproductive compensation occurs in families with a child with Cooley anaemia in this province. Genetic counselling, either before marriage or after the birth of the first affected child, had a significant effect on lowering the number of children born. 1 Medical Education and Research Centre, National Iranian Oil Company Health Organization, Shiraz, Islamic Republic of Iran (Correspondence to F. Habibzadeh: [email protected] RÉSUMÉ La thalassémie est la maladie héréditaire monogénique à transmission autosomique la plus fréquente dans le monde. La présente étude transversale reposant sur un questionnaire a évalué le comportement en matière de procréation de 156 mères d'enfants affectés par une β-thalassémie majeure (aussi appelée anémie de Cooley) dans la province de Fars (sud de la République islamique d'Iran). Sans tenir compte du nombre d'enfants affectés, les parents d'enfants atteints d'une anémie de Cooley avaient en moyenne trois enfants non touchés par la maladie, c'est-à-dire le même nombre que dans la population de la province. Les résultats indiquent qu'une compensation reproductrice se produit dans les familles ayant un enfant atteint de l'anémie de Cooley dans cette province. Les conseils génétiques, soit avant le mariage soit après la naissance du premier enfant affecté, ont eu un effet significatif sur la réduction du nombre d'enfants nés. ‫املتوسط‬ ‫لرشق‬ ‫الصحية‬ ‫املجلة‬ ‫عرش‬ ‫الثامن‬ ‫املجلد‬ ‫الثالث‬ ‫العدد‬ 24